The present invention relates to the production and processing lines of steel pipes and more particularly a novel arrangement of the so-called conditioning line in which such operations as end facing, internal cleaning, end threading, thread inspection, hydrostatic testing, etc., are performed.
In the past, it has been the practice so that if a steel pipe is rejected for example as a result of the thread inspection in the course of the conditioning operations so as to be reprocessed (or refinished), the reprocessing of the steel pipe to be reprocessed is effected by transferring it by a crane or the like to the position of a reprocessing machine which is remote from the conditioning line. As a result, it has been practically impossible to transfer the reprocessed steel pipe back to the conditioning line due to a large time lag (the transfer and reprocessing of the pipe require 20 to 30 minutes) and the next steel pipe being processed on the conditioning line. For this reason, it has been necessary to effect the operations subsequent to the reprocessing operation (e.g., the hydrostatic testing, marking and coating) on a separate line with the resulting considerable deterioration of the operating efficiency.